Both the milkweed tussock and the monarch caterpillars eat the cardiac glycoside-laden milky sap of milkweed.

When oleander aphids infested tropical milkweed, monarch butterflies laid fewer eggs on the plant, and the caterpillars developing on those plants were slower to mature.

The “king” of the Lepidoptera family, the monarch butterfly, is passing through the Lehigh Valley on the 3,000-year migration it makes each year.

Not including animals like the bald eagle or Eastern bluebird, the monarch butterflies have garnered much interest in people.

Oliver Hernandez poses with a common milkweed plant in his front yard in 2020. A tiny, young monarch caterpillar and even tinier monarch eggs are visible on the underside of a leaf.

Study highlights When oleander aphids infested tropical milkweed, monarch butterflies laid fewer eggs on the plant, and the caterpillars developing on those plants were slower to mature.

Planting milkweed is one of the easiest ways to support monarch butterfly populations, but this slip-up could actually cause ...

While exploring a patch of Milkweed, Evie came across a cluster of fuzzy, eye-catching caterpillars—Milkweed Tussock Moth caterpillars. Learn more about these lesser-known residents of Milkweed ...

As their name suggests, many milkweed species produce a milky-white substance that can be seen if their stem is broken.

"I planted a bunch of milkweed for the migrating monarch butterflies, but there’s a fuzzy orange, black and white caterpillar eating my milkweed. What should I do?" — P.R.

When oleander aphids infested tropical milkweed, monarch butterflies laid fewer eggs on the plant, and the caterpillars developing on those plants were slower to mature.